Yarn crimping apparatus



Oct. 20, 1959 R. s. BLEY YARN CRIMPING APPARATUS 2 Sheets-Sheet 1 Filed March 27, 1957 INVENTOR RudoL vh 3. Ba 7/ ATTORNEY Oct. 20, 1959 R. s. BLEY YARN CRIMPING APPARATUS Filed March 27, 1957 2 Sheets-Sheet 2 R Y m m E 0 W A 1 A B C W W M w n 2 2 A w United States Patent YARN CRIMPING APPARATUS Rudolph S. Bley, Milligan College, Tenn., assignor to 'Beaunit Mills, Incorporated, New York, N.Y., a corporation of New York Application March 27, 1957, Serial No. 648,829

9 Claims. (Cl. 28--62) The invention relates to the production of crimped thermoplastic yarn or, as it is better known, stretch yarn or stretch nylon. More especially, it relates to apparatus for producing stretch yarn by the so-called false twist method and in its more particular aspects the invention is concerned with improved means for setting the twist or crimp in the yarn.

The general method of crimping thermoplastic yarn with which this invention deals involves a false twist spindle through which the yarn strand passes while being pulled from a supply package. The false twist spindle is rotated at high speed and the yarn strand is so operated upon by the spindle that a twist is produced in a portion of the running length of said strand. The yarn is heated by external means in'that portion wherein it is twisted and since the yarn is of a thermoplasticnature,

the heating causes it to become soft or somewhat plastic i and upon cooling it retains the twist. This is one of the commercial methods of producing yarn having a high degree (approximately 100 percent) 'of stretch-ability and almost complete recovery. As is well known, such yarn has been widely used for making socks, underclothing and other garments.

A plant producing stretch yarn by the method briefly outlined or by any other method for that matter, is not commercially feasible unless it has several thousand spindles operating; that is, unless several thousand yarn strands are being operated upon simultaneously. With this many strands being twisted, it will be appreciated that the cost of heating the strands is a matter of considerable importance.

It is accordingly the primary object of the present invention to provide an improved means for efficiently heating a running yarn strand which is being twisted by the false twist method.

It is a further object of the invention to provide means as much as possible to that portion of the strand which is heated whereby the over-all efiiciency of the operation is increased.

Other and further objects, features and advantages of for confining the twist inserted by the false twist spindle the invention will become apparent as the description of Fig. 2 is a sectional view on a largerscale of the heati ing device of Fig. 1,

Fig. 3 is a view partially in side elevation and partially in section of a modified form of heating device and Fig. 4 is a plan view of a cap element which is useful in carrying out this invention.

Since the present invention deals with only certain aspects of the over-all yarn crimping operation it will not be necessary to describe the entire operation in detail but same has been shown diagrammatically in Fig. 1 and n will be briefly described in order'to further an underice v 2 standing of the utility of this invention. The non-crimped yarn is wound on a pirn 10 mounted upon a rail 11 and the yarn strand 12-is drawn from the pirn through a guide 13 and thence through a compensating tension device 14 and through an eye in the end of a tension sensing and regulating arm 15 of the tension device. After leaving the eye in the arm 15 the yarn strand passes upward through a heating chamber generally designated 16 and which will presently be described in detail. Located directly above the heating chamber 16 is a false twist spindle 17 which maybe of any suitable construction, the details of which are not a part of the present invention. It will be understood that each rotation of the false twist spindle inserts one turn of twist into the yarn strand and that the twist runs back along the strand through the heating chamber wherein the twist or crimp is set. After leaving the spindle 17, the yarn passes through a pigtail guide 18 and a traversing guide 19 and onto a spool 20, said spool being driven to take up the yarn by a cork covered roller 21 which bears against the yarn in order to pull the yarn strand at a constant speed. The heating chamber 16 comprises an inner chamber forming structure 22 which may be divided by a partition 23 into an upper section and a lower section, both of which are filled with a suitable heating fluid maintained at a constant elevated temperature by any desired means. Extending vertically through the chamber 22 and sealed thereto as by soldering as indicated at 24, or other suitable sealing means, is a thin walled tubular member 25. Snap rings 26 and 27 which fit into groovespiovided therefor in the ends of the tubular member 25 hold in position collars 28 and 29 of porcelain or other relatively low heat conducting material. The collars 28 and 29 bear against an outer "casing 30 of the chamber 16 and hold the tubular memb'er '25 and the associated chamber 22 in position 'withinsaid casing. Suitable insulating material 31 is provided between the inner chamber form ing structure 22 and the casing 30.

The tube 25 has a straight-line bore therethrough through which the yarn strand 12 passes without contacting the tube and is provided with outwardly protruding portions shown in Figs. 1 and 2 as being in the form of bulbous deformations 32 and 33. As the yarn strand moves rapidly up through the tube 25 it has a tendency to draw air up through the tubewith the result that the heated air in the tube is being constantly dissipated but this upward fiow of air through the tube is substantially reduced by means of the bulbous deformations 32 and 33. With this arrangement, the movement of .air through the tube tends to follow the sides of the tube and as air enters the lower bulbousportion 32 it swirls around in eddy current fashion before gradually leaking through the restricted bore of the tube into the upper bulbous portion 33 where again it'expands into the enlarged section of the tube and swirls around before passing on out through the top of the tube.

The bulbous portions 32 ,and33'not only cause the air to move more slowly through-the tube but also provide an outer surface area considerably greater than that of a cylindrical tube having a bore of the same diameter as the straight-line bore of the tube 25. This increased surface areaof course more effectively conducts the heat from the heating fluid contained within chamber forming structure 22 to the air within the tube and consequently to the yarn strand. While two bulbous portions have been shown in the drawing it will be understood that the tube maybe constructed with more than two. As indicated in the drawing by the line '34, the tube 25 is made in two pieces joined togethenat the partition. 23' but ofcourse the partition could be-rnade intwo'piecesinstead if desired. 9' s 1 It' is' contemplated that the 'tube 25'-will be made 'of black material so as to give off infrared rays at the temperature of the heating fluid. Thus'the tube may be formed of anodized aluminum, copper or brass or preferably of Karbate. This latter material has an outstanding thermal conduction characteristic and is used in the construction of chemical plants. It is a composition of carbon and graphite impregnated with a synthetic resin and is described in an article by L. C. Werking in Trans. Amer. Instit. Chem. Engrs., vol. 35, pp. 489-503 (1939) under the title: Carbon, Graphite and Karbate as Materials of Construction. If the tube 25 is made of aluminum or Karbate it may be desirable to provide collars of some other material around the tube at the points where it is sealed to the chamber 22 and cover 30 in order to provide a surface which may readily be soldered to these members, which preferably are made of steel.

To further slow the movement of air through the yarn heating tube 25, a conical cap 35 having an opening 36 aligned with the bore of said tube is secured to the upper side of the casing 30. A baflie 37 may be soldered to the inside of the cap 35, said baffle having a central opening 38 therethrough aligned with the opening 36 and being of such configuration as to tend to deflect air escaping from the tube back down into the tube. To facilitate the introduction of a thread-up wire into the top of tube 25, the cap 35 is made in two parts, as is best shown in Figs. 3 and 4. One of the parts is soldered to the casing 30 as indicated at 39 and the other is secured to said casing by means of a hinge 40 whereby the hinged part may be swung out of the way as indicated by dot-and-dash lines in Fig. 3. The cap and baflie are preferably made of the same material as the tube 25.

It has previously been mentioned that the false twist spindle 17 is rotated at high speed and in order to confine the twist inserted into the yarn strand to that portion of the strand wherein the twist will be set by the heating tube -25, a pair of twist barriers are provided. The twist barriers are in the form of a pair of rollers 41 and 42 located directly above the spindle 17 and a pair of rollers 43 and 44 located directly below the tube 25. The pairs of rollers bear directly against the yarn strand and elfectively prevent the twist from passing through them. The rollers may be spring urged toward one another or may be made of magnetic material so that they attract one another. By thus confining the twist as much as possible to the heating zone a higher degree of twist can be inserted into the yarn in that zone wherein the twist can be set, rather than have the twist extend into that portion of the strand wherein it will not be set because no heat is applied.

A modified form of heating tube is illustrated in Fig. 3 and indicated generally at 45. The tube 45 is mounted within the inner chamber 22, the bottom and top only of which are shown in Fig. 3, and positioned in the outer casing 30 in exactly the same manner as the tube 25 (Figs. 1 and 2). The major portion of the tube 45, at least that part of it which is located within the chamber 22, is shaped in the form of a spiral as indicated at 46 so that the air in passing upwardly within said tube takes a spiral path and hence moves slowly. The spiral form of the tube 45 also presents a large exterior surface to the heating fluid to thereby increase the amount of heat transmitted by the heating fluid to the air within the tube. It will be recognized that increasing the pitch of spiral 46 will retard the upward movement of air through tube 45 while decreasing the pitch of the spiral will permit a more rapid upward air flow. As is the case with tube 25, the tube 45 has a straightline bore therethrough through which the yarn strand .12 passes without touching the tube.

The tube 45 is made ofthe same material as used for the tube 25 and the conical cap 35 with baflle 37 is 4 positioned over the tube 45 in the manner previously described.

Thus it will be seen that basically the heating tube of the present invention is more etficient than a cylindrical tube for the purpose of heating the twisted yarn strand because the air within the tube is more effectively heated due to the large surface of the tube in contact with the heating fluid and further and particularly because of the fact that the heated air remains in the tube for a considerable period of time before being replaced by cool air which must be heated before it can be effective to set the twist in the yarn strand.

Having thus described several embodiments of the invention what is claimed is:

1. In yarn crimping apparatus wherein a yarn strand is pulled from a supply package, through a tension device, through a heating chamber, through a false twist device which causes a twist to run back along the yarn strand through the heating chamber where the twist is set into the yarn and wherein the yarn strand is wound into a package after leaving the false twist device; an improved heating chamber comprising a thin walled tubular member having a restricted straight-line passage therethrough through which the yarn strand passes without touching said member, said member having a portion protruding outwardly from said restricted straight-line passage so as to impede the passage of air therethrough and to provide an external surface area substantially larger than that of a cylinder which would fit snugly within the passage through said member, a chamber surrounding a major part of the length of said tubular member, and heating fluid in said chamber in contact with the external surface of said tubular member.

2. In yarn crimping apparatus wherein a yarn strand is pulled from a supply package, through a tension device, through a heating chamber, through a false twist device which causes a twist to run back along the yarn strand through the heating chamber Where the twist is set into the yarn and wherein the yarn strand is wound into a package after leaving the false twist device; an improved heating chamber comprising a tubular member having a restricted straight-line bore therethrough through which a yarn strand is adapted to be drawn while in twisted condition, said member having portions which protrude outwardly from said bore whereby air passing through said tube is apt to follow the configuration of said portions and thereby move slowly through said tube, said portions also causing said member to have a substantially larger exterior surface than a cylindrical tube having an equal size bore, a container for heating fluid surrounding said tubular member in such manner that heating fluid will be in direct contact with said tubular member, and heating fluid in said container.

3. In yarn crimping apparatus wherein a yarn strand is pulled from a supply package, through a tension device, through a heating chamber, through a false twist device which causes a twist to run back along the yarn strand through the heating chamber where the twist is set into the yarn and wherein the yarn strand is wound into a package after leaving the false twist device; an improved heating chamber comprising a tubular member having a restricted straight-line bore therethrough through which a yarn strand is adapted to be drawn while in twisted condition, said member having portions which protrude outwardly from said bore whereby air passing through said tube is apt to follow the configuration of said portions and thereby move slowly through said tube, said portions also causing said member to have a substantially larger exterior surface than a cylindrical tube having an equal size bore, a container for heating fluid surrounding said tubular member in such manner that heating fluid will be in direct contact with said tubular member, heating fluid in said container, a cap disposed above the upper end of said tubular member for restricting the escape of air from said member, and said cap having an opening aligned with the bore of said tubular'member whereby the yarn strand may pass in a straight-line path through said bore and said opening.

4. In yarn crimping apparatus wherein a yarn strand is pulled from a supply package, through a tension device, through a heating chamber, through a false twist device which causes a twist to run back along the yarn strand through the heating chamber where the twist is set into the yarn and wherein the yarn strand is wound into a package after leaving the false twist device; an improved heating chamber comprising a tubular member having a restricted straight-line bore therethrough through which a yarn strand is adapted to be drawn while in twisted condition, said member having portions which protrude outwardly from said bore whereby air passing through said tube is apt to follow the configuration of said portions and thereby move slowly through said tube, said portions also causing said member to have a substantially larger exterior surface than a cylindrical tube having an equal size bore, a container for heating fluid surrounding said tubular member in such manner that heating fluid will be in direct contact with said tubular member, heating fluid in said container, a cap disposed above the upper end of said tubular member for restricting the escape. of air from said member, said cap having an opening aligned with the bore of said tubular member whereby the yarn strand may pass in a straight-line path through said bore and said opening, and said cap containing a baflle disposed above the upper end of said restricted straight-line bore and tending to direct the air escaping from said tubular member back down into said member.

5. In yarn crimping apparatus wherein a yarn strand is pulled from a supply package, through a tension device, through a heating chamber, through a false twist device which causes a twist to run back along the yarn strand through the heating chamber where the twist is set into the yarn and wherein the yarn strand is wound into a package after leaving the false twist device; the improvement comprising a tubular member having a restricted straight-line bore therethrough through which a yarn strand is adapted to be drawn while in twisted condition, said member having portions which protrude outwardly from said bore whereby air passing through said tube is apt to follow the configuration of said portions and thereby move slowly through said tube, said portions also causing said member to have a substantially larger exterior surface than a cylindrical tube having an equal size bore, a container for heating fluid surrounding said tubular member in such manner that heating fluid will be in I direct contact with said tubular member, heating fluid in said container, and a twist barrier located closely above the false twist device and a second twist barrier located closely below said tubular member, each of said twist barriers comprising two members arranged to contact each other and to engage the yarn strand between them to confine the twist inserted by the false twist device to that portion of the yarn strand located between said barriers.

6. In yarn crimping apparatus wherein a yarn strand is pulled from a supply package, through a tension device, through a heating chamber, through a false twist device which causes a twist to run back along the yarn strand through the heating chamber where the twist is set into the yarn and wherein the yarn strand is wound into a package after leaving the false twist device; the improvement comprising a tubular member having a restricted straight-line bore therethrough through which a yarn strand is adapted to be drawn while in twisted condition, said member having portions which protrude outwardly from said here whereby air passing through said tube is apt to follow the configuration of said portions and thereby move slowly through said tube, said portions also causing said member to have a substantially larger exterior surface than a cylindrical tube having an equal size bore, a container for heating fluid surrounding said tubular member in such manner that heating fluid will be in direct contact with said tubular member, heating fluid in said container, a cap disposed above the upper end of said tubular member for restricting the escape of air from said member, said cap having an opening aligned with the bore of said tubular member whereby the yarn strand may pass in a straight-line path through said bore and said opening, and a twist barrier located closely above the false twist device and a second twist barrier located closely below said tubular member, each of said barriers comprising two members arranged to contact each other and to engage the yarn strand between them to confine the twist inserted by the false twist device to that portion of the yarn strand located between said barriers.

7. A yarn crimping apparatus as set forth in claim 1 wherein the portion protruding outwardly from said restricted straight-line passage has a bulbous configuration.

8. A yarn crimping apparatus as set forth in claim 1 wherein the portion protruding outwardly from said restricted straight-line passage has a spiral configuration.

9. A yarn crimping apparatus as set forth in claim 5 wherein the contacting members of said twist barriers are of magnetic material and at least one of said members is magnetized so that said members are urged toward each other.

References Cited in the file of this patent UNITED STATES PATENTS 1,005,441 Lovekin Oct. 10, 1911 1,787,904 Heyward Jan. 6, 1931 2,790,298 Kunzle Apr. 30, 1957 

